From Wikipedia, the free encyclopaedia, I found the following definition:
A samovar (Russian: самова́р, literally "self-brewer") is a heated metal container traditionally used to brew tea in and around Russia, as well as in other Slavic nations, Iran and Turkey.

A traditional samovar consists of a large metal container with a faucet near the bottom and a metal pipe running vertically through the middle. The pipe is filled with solid fuel to heat the water in the surrounding container. A small smokestack is put on the top to ensure draft. After the fire is off a teapot could be placed on top to be kept heated with the passing hot air. The teapot is used to brew the заварка (zavarka), a strong concentrate of tea. The tea is served by diluting this concentrate with кипяток (kipyatok = boiled water) from the main container, obtaining a lighter or darker brew function of drinkers' tastes.

"To have a sit by samovar" means to have a leisurely talk while drinking tea from samovar, and it is a Russian expression reflecting the popular attitude towards its use.

In older times it was an economic continuous source of hot water. Various slow-burning items could be used for fuel, such as charcoal or dry pinecones. When necessary, the fire in the samovar pipe was quickly rekindled with the help of bellows manufactured specifically for this use.

In modern times, the samovar is mostly associated with Russian exotica and nostalgia. During the Olympic games of 1980, an incredible amount of samovars were sold to visitors from abroad, thus affecting the samovar: it gained international recognition and became a symbol of Russia.